I have an unlocked GSM smartphone. I am currently in the USA and I am programming some number into the phone.

I have been putting then in like +44 01XXXX..., etc. Should I remove the country code from the phone numbers? I will have a UK SIM card with a UK phone number.

With the +44 will it not dial out will this get charged at a long distance rate? My assumption was it would be like dialing a 1-800 number in the US where if you include the country code in country it just ignores it. I added USA phone numbers as +1 since they will definitely be international.

Is it okay to leave all the numbers in the full international format or should I change all of the numbers? Also, if I can keep the +44 should I also include or exclude the leading zero on some phone numbers? on my phone it puts in logical spaces in the display if I got +44 1 XX... without the zero, but mashes it all together if I go +4401XX...

  • Leaving + sign is ok, it will not be charged as international, I do not know where you got that idea from. Regarding the leading zeros (00) it will not work in the US, just use the + sign. In the US they use (011) instead of (00). Commented May 16, 2015 at 21:15
  • Incidentally, the 1 in 1-800 in the US isn't the country code; it's the trunk prefix in the NANP, which was traditionally required for long-distance calls. It's just that the NANP "country code" was selected to be the same as the established NANP trunk prefix.
    – cpast
    Commented May 16, 2015 at 21:26

1 Answer 1


It has no disadvantages to you to use the international phone format when calling from a GSM or newer technology cell phone. If you are calling a national subscriber with the international prefix, your call will still be billed as a national call. YMMV in other, older cell networks, if you should happen to find something like that.

The obvious advantage to always use the international format is that you can use the stored number even if you are abroad.

The procedure on how to dial a national phone number from abroad is different from country to country. Although there are exceptions, there are however a few general rules, which mostly work:

  • If the country you are calling to has no area codes, the national number usually follows the country code without modifications. Using the national, Norwegian number 22012345 as an example, you would dial this number as +4722012345 from abroad. In countries without area codes, it is not uncommon that regular phone numbers start with a 0, where the 0 is a part of the phone number and must be dialled from abroad, e.g. the Italian national number 0612345678 should be dialled +390612345678 from abroad.

  • If the country you are calling to has area codes, the national number usually follows the country code after omitting the trunk prefix. The trunk prefix is usually the first digit of the area code and is from a technical view not considered as part of the phone number, but as a signal to call someone outside your own area code. In most countries with area codes, like e.g. in the UK, the trunk prefix is 0. So if you have a UK national number 01234 556677, you would dial this from abroad as +441234556677 (leaving out the 0 between +44 and 1234).

As a side note, be aware that the leading 1- in US phone numbers is not a trunk prefix in the same sense that a trunk prefix is used in most other countries (leading digit of the area code), but a prefix usually required if you are calling someone outside your free local call area and hence rather a kind of acknowledgement that you accept the charges for the call you are making. The equivalent to a trunk prefix in the North American numbering plan was traditionally the second digit of the area code, which used to be 0 or 1, while local phone numbers had only numbers 2-9 as the second digit.

One exception from these rules is e.g. Switzerland. Although originally a trunk prefix, all regular, Swiss phone numbers now have a leading 0 as the first digit. This 0 is part of the phone number and must always be dialled within Switzerland, it should however be omitted, when calling a Swiss number from abroad. The national number 0441234567 should be dialled as +41441234567.

  • Very detailed, I have some numbers for both France and UK that will be stored in the phone contacts. I think I will just setup the numbers using the + prefix for all as it sounds like it will work to whatever number given whatever sim I picked up. I guess if it doesn't dial I'll have go back and figure it out. In your second bullet point example for the UK with the leading zero, should it still work if the zero is there?
    – HelpEric
    Commented May 17, 2015 at 3:03
  • @HelpEric no, when the 0 should be omitted it will not work when it is there. But as you now know the problem is likely to be in the fist digit, you can easily adjust the number and try again.
    – Willeke
    Commented May 17, 2015 at 8:33

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